Your database will crash.
Originally posted by newcomer
Hi All,

If I will loose one of the log members in a group - when my Datbase is up and running, does oracle write that information in ALTER file?

I mean, without shutting down my database and bouncing it back or withour querying status in v$logfile , is there any way to know that members got deleted.

Thanks
Yes, it will write a trace file in which you can see the missing and also in the alert log something like this including trace file:
ORA-27037: Message 27037 not found; No message file for product=RDBMS, facility=ORA
SVR4 Error: 2: No such file or directory
Additional information: 3
LGWR: terminating instance due to error 313
Instance terminated by LGWR, pid = nnnnn

HTH